For those who have added an air/oil seperator.... - PeachParts Mercedes-Benz Forum

4thesporty · #1 10-19-2010, 01:26 PM

I am pondering the idea of adding an air/oil seperator to my 85. The factory one is just so messy and I would like to have a clean bay.

I would like the Mann provent 200 if I can find one for a decent price

or something similar.

My question is, if I wanted for it to drain back to the oil pan, how are you all tapping into that factory drain line?

Or, if I should decide to use a catch can, how are you all blocking, or deleting that factory drain tube?

Thanks,

Diesel911 · #2 10-19-2010, 10:01 PM

On my 84 300D where the Drain you are speaking of is it is a nipple that sticks up that has a groove for an O-Ring. It only sticks up about 1/2 inch. The Draing Tubing is belled wider than the rest of the tubing and slides over it.
Below that in the upper pan casting is a one way valve to keep the Crankcase Pressure from pushing up the tube.

A Rubber Hose could simply be attched to the Nipple with a Hose clamp (not much room to fit a Screwdriver down there though.
When I did the stuff in the below thread I wanted to make a larger Breather/Oil Separator then I ended up with. But, since the Oil drains by Gravity any tubing or Hose has to have a nice un-kinked down wards path.
I ended up just taking the easy way out and using the stock tubing.

Washable Air Filter and Intake Mod , With Larger Breather
Washable Air Filter and Intake Mod , With Larger Breather

When I have taken the lid off of the Breather I am finding no pool of Oil in there so the Oil must be draining OK because the Hose that goes to the Intake is higher than the Drain Hole.
However, I can sometimes see wiffs of Blowby seeping out from under the lid, which is not sealed. So, when I can think of something better I will change it.

vstech · #3 10-19-2010, 10:10 PM

have you tried to change the o-rings in the OE separator? that coupled with a sealed separator should eliminate the mess. my 82 works fabulous and does not leave any mess now that I have cleaned and repaired the original one.

4thesporty · #4 10-20-2010, 11:21 AM

Perhaps I will do the O-rings first as it is a cheap attempt at a fix. If I still have problems I'm going to be looking for a resonably priced seperator.

Thanks for the suggestions.

Decisions, Decisions......

4thesporty · #5 11-06-2010, 09:00 PM

I replaced the O-rings on my factory separator drain line. I did the one where the air cleaner connects to the pipe and the one where the pipe connects to the oil pan.

Also, I cleaned well and sealed the separator with some RTV.

Will clean engine bay well tomorrow and drive for a week and see what happens.

JHZR2 · #6 02-25-2011, 08:52 AM

If you seal the separator, how does the blowby gas get out? I assume there is some gas that carries the oil vapors, which needs to get sucked back into the engine, not forced through the separator into the oil pan...

What am I missing?

Thanks!

vstech · #7 02-25-2011, 09:06 AM

Quote:

Originally Posted by JHZR2

If you seal the separator, how does the blowby gas get out? I assume there is some gas that carries the oil vapors, which needs to get sucked back into the engine, not forced through the separator into the oil pan...

What am I missing?

Thanks!

you seal the lid to the separator, it still has the openings top and bottom for pressure/vacuum...

JHZR2 · #8 02-25-2011, 09:18 AM

OK, guess Im just not remembering mine right. I thought there was an opening for the valve cover to go into the separator (through the AF cover), and then an opening at the bottom for it to go down the drain tube into the oil pan via the check valve.

So there is another port on the separator someplace that provides the induced draft to remove the blowby gas once the oil has separated out?

Thanks for the clarification. I think Ill be doing this job this weekend to see if it keeps the oil out of my turbo intake U-tube and dripping down the wastegate and elsewhere. My actual oil use is not measurable, and I dont get any on the air filter itself, but the little bit of oil that is there sure makes a mess on the underside of my car...

Thanks!

vstech · #9 02-25-2011, 09:39 AM

yeah, there is a third entry port on the top lid of the separator, it's got a u shaped tube that goes into the turbo intake hole of the air cleaner.
it's a pretty loose fit. I disassemble that tube, and the lid of the separator, and seal it up with ultra black silicone. so vapor and oil ONLY go where they are supposed to.

funola · #10 02-25-2011, 09:44 AM

My 83 240D parts car has a soda can size foam covered container for the oil mist drain. Is that a better system than what's on my 83 300D turbo? Has anyone swapped one over to the 300DT?

vstech · #11 02-25-2011, 10:12 AM

it would be difficult to swap that system into a turbo... you'd have to cut into the air filter u tube, somehow... or frankenstein some type of adapter into the air filter...

mikeyfev1 · #12 02-25-2011, 10:19 AM

This is all very interesting and timely for me.

I have an 85 300D KaliKar and I'm having lots of oil splatters under the hood. After a good engine cleaning I notice:

oil all around the rubber tube fitting on top of the valve cover
oil on the bottom side of the hood over the air cleaner (remember, my air cleaner is right behind the passenger-side headlight). This is heavy enough that when I open the hood I get oil drips coming down from the hood.
after a wipe-off the oil is back just as badly after a couple of drives.

And I keep reading about oil separators, etc. On my car, there is a tube running from the top of the valve cover to the top of the air cleaner. Along the way there is a T-fitting with a branch running to the intake of the turbo. That's it, no other devices of any kind connected to this line. Has someone removed something from my car?

kerry · #13 02-25-2011, 10:21 AM

Quote:

Originally Posted by vstech

it would be difficult to swap that system into a turbo... you'd have to cut into the air filter u tube, somehow...

The OE 79 SD U-tube has a built in fitting to accept a PCV tube.

vstech · #14 02-25-2011, 10:23 AM

ya, I've got a pair of those from my euro's...

4thesporty · #15 02-25-2011, 10:29 AM

Just an update to my original problem in October:

I am not getting an oily air filter anymore, but I do have some oil leaks on my U-tube from the AC to the turbo. I will replace those seals in the near future as well as the gasket underneath the turbo and hopefully all oil leaks will stop in that area.

It would be so nice to not have to clean the pan under my car in the garage!